Brighton and Hove Bus Company could be forced to share its depot with rivals or even hand over routes after an anticompetition investigation was launched.

After months of deliberation, the Office of Fair Trading (OFT) has decided to refer the UK’s £3.6 billion local bus service industry, excluding London and Northern Ireland, to the Competition Commission.

The commission will launch an investigation into the country’s major operators, including Arriva, FirstGroup, Stagecoach, National Express and Go- Ahead, owner of Brighton and Hove Buses.

If it rules there is an unfair monopoly in an area the dominant operator could be forced to share a depot, sell some of its assets or bring in multi-ticket agreements.

The OFT estimates bus fares in areas where only one of the large national groups offers services are 9% higher than in regions where two or more big players operate.

Heather Clayton, OFT senior director, said: “The OFT believes it is appropriate for the Competition Commission to investigate how, in its various forms, competition can be harnessed to deliver what passengers want and the best value for money for the taxpayer.”

Roger French, managing director of Brighton andHove Buses, branded the investigation “a complete waste of time, resources and money”.

He said an independent assessment of the OFT’s conclusions, particularly its 9% claim, found them to be based on “spurious” data.

Mr French said: “There is an agenda at the OFT when it comes to the bus industry.

“I think the commission inquiry will conclude the bus industry, for all its faults, does a very good job.”

He said his company’s takeover of Brighton Blue Buses in 1997 and Stagecoach’s routes around Lewes and Seaford in 2005 showed consolidation was needed.

Tom Druitt, founder of the Big Lemon Bus Company, that runs an eco-friendly service between the universities and the centre of Brighton, took the opposite view.

He said: “Although I don’t think there is overt discrimination against smaller entrants into public transport, the system is set up in a way that you need the financial muscle to compete.”

Mr Druitt said his services were often ignored by bodies such as the council and the NHS when they display information about public transport on their websites.